Radon Mats Frequently Asked Questions
Check your Radon System for Red Flags
Check your Radon System for Red Flags
Was your radon system installed by a certified pro or an amoral charlatan?
Walk around your home and take a look at your radon system. If you see any of these red flags, there’s a good chance your system does not work. Have a certified radon mitigator come out and inspect the system for damage or repair. See below for the most common red flags. Be sure to perform a radon test first and foremost or use an EcoSense Radon Monitor to check room to room variations.
U Tube Manometer at Zero
Manometers measure the pressure in your radon system. Typically they look like this.
This is called a U-tube and it is the most commonly installed manometer. It is normally found inside the home on the radon pipe. It can be anywhere on the suction side of the system (i.e.. below the fan).
If you can’t find a manometer or U-tube on your home, that is a huge red flag. That means your contractor either doesn’t know how they work or wanted to pocket an extra $10.
Most U-tubes have a scale from 0 to 4.5. It is read as “inches of water column pressure.” The only “bad” U tube reading is ZERO (or an even reading across both columns). Zero means your fan is off or unplugged. It means you have as high or higher radon levels than if you had no system at all! It could be as simple as buying a new fan, or there could be some other red flags to check on. All you need to know is: zero DOES NOT mean “zero” radon, quite the opposite. If you can’t read the U tube, call PDS and we’ll help you through it. Radon fans have an average lifespan of eight years. The most common technical calls we get are about U tube readings and dead fans. There are many, many radon systems out there with dead fans and homeowners that don’t know it. Check your U tube (Demonstrated Here); test your home!!! Watch our one minute install video at the bottom of this page. You can learn about reading a fan curve here
“U bends” or right angle exhausts
“U bends” or right angle exhausts
Radon systems should exhaust above the eve of the roof and straight up in the air (according to most standards). Unlicensed installers are afraid of rain. They believe that radon systems will fill with rain water and flood basements if they exhaust straight up in the air. This couldn’t be further from the truth. A typical radon fan moves anywhere from 50 to 300 cubic feet of air per minute from under your soil out above your roof. A cubic foot of air is about the size of a basketball. Imagine 50 basketballs firing out your roof every minute! Not a drop of rain will make it inside your pipe! A U bend or 90 degree bend is especially dangerous as it directs radon gas (a CLASS A carcinogen) back toward the ground and re-entry points like doors and windows. It completely disrupts the entire purpose of the system. A “U bend” is the biggest red flag when inspecting a radon system as it means the contractor didn’t take a single course and simply went with their gut instincts.
Radon fan in the crawlspace or basement
Radon fan in the crawlspace or basement
The only acceptable radon fan placements are outside the thermal envelope of the home, typically: in the attic, outside the home, or in a garage with no occupied living space above. If the exhaust side of a radon system is compromised in any way, not only will the system not mitigate the radon, it can actively fill your home with more radioactive gas!
This is not as far-fetched as you might think. Imagine a fan in a crawlspace, the homeowner enters to move some Christmas decorations and unknowingly bumps the radon system, then a small leak forms and this system now leaks 5-10 cfm of radon gas into the crawlspace. Radon is colorless and odorless. No one will find this error until a radon test is performed. Scenario B, the home’s foundation settles and the radon pipe slowly moves a few centimeters to the side, creating a space between the fan couplings and PVC pipe. You have another leak that won’t be found until a radon test is performed. For all these reasons and more, stick to the code and test your home every two years as the US EPA suggests.
Extension cord to radon fan
Extension cord to radon fan
Exterior 110V radon fans need to be hard-wired and have a dedicated shut-off switch nearby. Class II low voltage radon fans, like the KTA 150, are excluded from this requirement in most jurisdictions. Unlicensed installers will often cut corners, not pull electrical permits, and run long extension cords to radon fans. This is illegal and should be reported. Maximum cord length is 6′ and should never penetrate a wall. Acceptable corded locations for standard voltage fans are in attics or garages.
Exhaust under eve or near window
Exhaust under eve or near window
Radon fans should exhaust above the eve of the roof, straight up in the air (or at a 45 degree angle as of 2019), and be at least ten feet away–or two feet above–doors or windows. Oftentimes you will see exhausts under eves or near windows. The moist soil air will rot your soffits (an expensive mistake) and allow the radon to re-enter through the windows. The awful system below would be shooting radon into the basement window if the fan hadn’t already died five years too soon after being filled with condensation.
Schedule 20 pipe
Schedule 20 pipe
The most common radon system component is schedule 40 PVC pipe. Schedule 40 is thick enough to resist cracking and leaking radon gas. Unlicensed installers will often use schedule 20 pipe because it’s cheaper. However, schedule 20 pipe is known to crack extremely easily, especially in cold temperatures or after UV exposure. You can often distinguish between the two by sight. Schedule 20 pipe yellows quickly and easily; it is about as thin as your fingernail. While schedule 40 PVC is nearly a quarter inch thick. It is white and resists yellowing for many, many years. Curious about PVC size requirements? Click here to read about sizing
Horizontal radon fan
Horizontal radon fan
Radon gas is a soil gas. Soil gases contain lots of moisture. If a radon fan is installed horizontally, it turns into a water pump. This voids the warranty, as the fan will typically short out in a few months. No trained and licensed installer would ever put a fan in horizontally. The image below violates half a dozen radon codes and does nothing to help the homeowner. Inoperable and shameful system.
Metal or HVAC fan
Metal or HVAC fan
Again, due to soil moisture, radon fans have very high moisture protection for their motors. Metal fans, typically used in HVAC duct systems, do not have these protections. These fans will typically fail within weeks or months of install and are not covered under warranty when installed on a radon system. Some HVAC, plastic inline fans will have similar model numbers and specs as compared to radon fans, but be 50% cheaper. The reason is: they do not have the same moisture protection. You will see these fans fail many, many years before a comparable radon fan would. Fantech renamed all their radon fans in 2018 for this exact reason.
Unsealed or loose vapor barrier in crawlspace
Unsealed or loose vapor barrier in crawlspace
Corner cutters are lazy. Many suction pit systems fail becuase a pro couldn’t be bothered to pull out four buckets of dirt.
Those same corner cutters often don’t seal their vapor barriers. They lay them down like a “magic blanket” and hope the inspectors don’t know any better. Unfortunately, their often right. An unsealed vapor barrier acts just like an open window; it can lower your radon but at what cost? Your HVAC bill will thank you if you can install the barrier correctly
3" PVC directly into a slab
Unsealed or loose vapor barrier in crawlspace
How can you pull out 15+ gallons of dirt out of a 3.5″ hole? You can’t. If you see a 3″ or even a 4″ PVC straight into your floor, odds are they cut some corners and oversized a loud radon fan or simply just gave you a bad system. Learn more about proper pit design here
Open Sump Pit or other unmitigated foundations
Unsealed or loose vapor barrier in crawlspace
Sealing is the key to an efficient radon system. Our entire industry wouldn’t exist if the wind blew the right direction and everyone lived with their windows open all the time–but that would be a ludicrous solution to our soil gas problem, right?
It’s just as ludicrous to mitigate part of a home and leave other open foundation drains, sumps, crawlspaces, or penetrations wide open. Odds are, your radon fan is pulling air from those penetrations and throwing it outside: literally. That is air your HVAC has to make up for and you have to pay for.
No installer sticker or signature
No installer sticker or signature
Professionals stand by their work and put their contact information on their systems. Fly-by-night contractors looking to make a quick buck do not. Simple as that. Click the yellow button below to find a pro in your area.
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Red Flag Video Library
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